Sensible inputs vital for almond grower Chuck Dirkse

Chuck Dirkse has adopted a wide range of almond production practices designed to improve the long-term sustainability and productivity of his farm.

Greg Northcutt | Mar 04, 2014

When you’re growing a crop like almonds, in which an orchard can take at least three years after planting to produce its first marketable crop and can remain productive for another 20 years or more, you’re in business for the long haul.

That’s why Stanislaus County almond grower Chuck Dirkse has adopted a wide range of production practices – such as targeted application of water, pesticides and crop nutrients and enhancing habitat in the orchards to attract predator-controlling animals – designed to improve the long-term sustainability and productivity of his family’s farming operation.

“We’re dependent on a healthy environment as well as favorable economic conditions,” Dirkse says. “We aren’t an organic farming operation. But, we believe it’s important to care for the environment. Incorporating sustainable farming practices into our daily routines helps protect both the environment and our profitability.”

The family-owned La Mancha Orchards features 310 acres of almonds growing on two ranches near Denair, Calif., In addition to Nonpareil the varieties include Avalon, Carmel, Fritz, Monterey and Wood Colony. The trees range in from 9 and 10 years of age to 25 and older.

Production numbers

Last year, Dirkse harvested his second largest crop ever. That’s despite the unusually heavy pressure from navel orangeworm that he and other California almond growers experienced.

However, kernel size was smaller than usual. In fact, warm spring temperatures stunted nut development, resulting in some of the industry’s smallest kernels in four decades.

Dirkse reports that turnout or nut meat percentage of his Nonpariel, the industry’s bread-and-butter variety, was down from 2011. That’s when a long, extended bloom and unusually vigorous bees contributed to a record size crop for La Mancha Orchards. “I don’t think I’ve ever seen the trees so completely full of blossoms as they were that year,” Dirkse recalls.

In 2011, yields of 8th leaf Wood Colony trees, one of his two blocks of that variety, topped 4,200 meat pounds per acre. Meanwhile, his top-performing Nonpareils that year, a block of 8th leaf trees, yielded an average of around 3,500 pounds of nutmeats per acre.

Dirkse was a member of the first class to participate in the Almond Board of California’s Almond Industry Leadership Program in 2009. This one-year program encourages individuals within the almond industry to participate in leadership training and to take a leadership role in the future of the industry. Now, he’s serving in his second year as a mentor for that program. “It’s a fulfilling way to give back the kind of help that was given to me,” he says.

Making every drop count

In 2010, Dirkse took part in the launch of ABC’s first sustainability education modules on irrigation and nutrient management. This self-assessment program also covers energy efficiency and air quality. It enables growers to compare their current farming practices with a set of best practices that make practical and economic sense in terms of sustainability, profitability and the environment.

Whether water, nutrients, fungicides, insecticides or other materials, La Mancha Orchards’ sustainability program is based on using a production input only when and in the amount needed.

“For example, we don’t apply a chemical or fertilizer just because it’s always been done,” Dirkse explains. “We have to have a good reason to use it. If it’s really needed to solve a specific problem, we’ll put it on. But, we don’t use any more than we have to. That saves money and it’s better for the environment.”

• Using water-conserving irrigation systems that apply water only around the tree. He uses a double-line drip system on one ranch, which features more rolling terrain, and micro jets on the other, where the ground is flatter. Eliminating the use of water between tree rows also limits any weed growth, reducing the time and expense of chemical or mechanical weed control. To improve water use efficiency, Dirkse irrigates his orchards based on readings from soil moisture meters, which he’s installed at the rate of one every 50 acres, and ET rates.

• Shredding tree prunings instead of burning them. Doing this over a number of years has prevented the release of tons of carbon into the atmosphere and improved the soil by returning organic matter and nutrients to the ground, Dirkse reports.

• Growing an annual cover crop, such as native grasses, between the tree rows. Also, he’s trying to incorporate more bee forage, like mustard. This vegetation increases water absorption by the soil, while controlling erosion and dust. During the growing season he mows this vegetation as needed. Meanwhile, he uses a combination of pre-emergent and burn-down herbicides to keep the orchard floor under the trees clean to minimize debris at harvest when picking up and processing the nuts.

• Enhancing habitat in the orchard to attract insects, birds and other animals that feed on crop pests. A natural alternative to pesticides, these practices include providing nesting boxes for barn owls that help control gophers.

A lesson in worm control

Timely application of insecticides when populations have reached threatening levels has helped keep his two major insect pests -- navel orangeworm and peach twig borer – under control, Dirkse notes.

As a result of last year’s unusually high navel orangeworm pressure, 0he plans to start his NOW hull split sprays a little earlier than he has before. Also, he’ll change the way he sprays the trees. In the past, he’s treated the individual rows of trees. That takes several days before he finishes up by spraying the ends and edges of the field. Now, he’ll start on the outside and then work his way up and down the rows. This will give him a head start on the pests, he explains, since the moths move from the borders to the interior of the orchard as they lay their eggs in the spring.

“Last year, the majority of worms we found during harvest were on the ends and borders of the fields.”

Drilling for Water

This past winter, though, his overwhelming concern has centered on water – will he have enough for his trees this season as the drought continues, following California’s driest year in 119 years of record keeping? With no access to any surface water, even if it was available, he depends entirely on his wells to irrigate his trees.

This past winter, with little rain falling on his orchards, he was irrigating the trees about once a week. “I try to simulate rainfall over the winter so that the soil profile is moist enough to support a good bloom,” he says. “That’s when they need a lot of water to push petals and leaves.”

In January, water levels in his wells were in good shape, Dirkse reports. However, he plans to deepen one of his wells and replace another, which is 60 years old, in an attempt to reach cleaner water.

“Everyone I’ve talked to indicates they’ll be putting in new wells this year,” he says. “Even with the existing wells, the water table normally drops during the season as the weather warms and the trees’ water needs increase. As other growers drill new wells, my fear is that there won’t be enough water for everyone. I wake up at night wondering what I should do.”